Camera shutter mechanism with synchronizer



June 16, 1953 w. L. LAWSON CAMERA sHuTTER MECHANIM WITH sYNcHRoNIzER 2Sheets-Sheet l Filed March 11, 1948 June 16, 19.53 w. L. LAwsoN2,6415978 CAMERA SHUTTER MECHANISM WITH SYNCHRONIZER Filed March l1,1948 2 Sheets-Shee't 2 [Z] ATTORNEY Patented June 16, 1953 CAMERAsnUr'rEa MEcHANlsM WITH sYNcHRoNIzER William L. Lawson, Forest Hills,NQY., assignor to Whitehouse Products, vInc., Brooklyn, YN. Y., acorporation of New York Application March 11, 1948, Serial No. 14,301

4 Claims. (Ci. 95--11.5)V

'I'his invention relates to a camera shutter f mechanism, and moreparticularly is directed to ashutter mechanism for a camera adapted totake pictures using fiash lamps.

Many efforts have been made in the camera field to devise a shutterwhich will be simple in operation. easyand economical to manufacture andstill capable of giving reliable exposures over a long period of timewith consistent and controlled exposure speeds.v While many shuttershave been designed to achieve these objectives, it is frequently foundthat either they have t be carefully hand made in order to achieveprecision, `or else they vary considerably in exposure speeds from onecamera to another ii' made by mass production methods.

One object of this invention is to provide a simple camera shutter thatcan be made by mass production methods and still provide reliableoperation for a long period of time with a uniform regulated time ofexposure.

A further object of the invention is to provide such a camera shutterfor a photoflash4 camera in which the synchronization of the light fromthe flash lamp and the exposure of the iilm are Figure 8 is a frontelevational view of the 'ape-rture or cover blade `of the shutter.

Figure 9 is a diagrammatic wiringi diagram showing the connection of thebattery and flash lamp to theiiash switch in the shutterv housing.Referring particularly to Figure 2, the shutter mechanism is mounted inthe front compartment Ill of a. shutter housing II, which may be made ofmetal, molded plastics or other suitable material, and has a Wall I2provided with a central exposure opening I3. A suitable lens system,such 'as a lens I4 mounted inside the shutterand the lens I5 mounted inthe cover plate I6 for the shutter housing may be provided, the film inthe camera being positioned for taking 1 pictures to the'right of thelens I4, as seen in Figure 2.

The shutter mechanism is best seen by reference to Figures 1, 3, 4 and5, showing the mechanism in the'housing II with the cover or face plateI6 removed. This mechanism may consist synchronized toproduce reliableand consistent results.

Other objects andr advantages of my invention will be explained and willbe apparent Yfrom the following description of a preferred form of myinvention shown inthe drawings, in which Figure 1 is a front elevationalview of a camera shutter constructed in accordance with my invention butwith the housing cover plate removed, the shutter being in a position ofrest before an exposure is made.

Figure 2 is a transverse sectional view through the camera shutter andhousing including the cover plate over the shutter mechanism, and takenapproximately on the line 2-2' of Figure l.

Figure 3 is a view similar to Figure 1, but showing the shutter bladesand otherparts advanced to a position just before an exposure is made.

Figure 4 is a View similar to Figure l, but show-V ing the shutterblades and other parts in the position occupied at the approximateinstant of starting an exposure.

Figure 5 is a view similar to Figure 1, but showing the shutter bladesand other parts in the po sition occupied immediately after completionof an exposure.

Figure 6 is a fragmentary horizontal sectional view taken approximatelyon the line 6 6 of Figure 1.

Figure I is a front elevational view of the ex 55: integraltherewith.The exposure-blade is pref-- posure -blade of the shutter. 4

of an aperture blade I'I pivotally mounted for rotation about the fixedstud I8 secured in or to the housing wall I2. An exposure blade I9 ispivotally mounted on the Ystud 20 fixed to the aperture blade I'I at apoint laterally offset from the stud I8. A single spring may be used tooperate the exposure blade I9 and also to restore both blades to aposition of rest after an exposure is made. This may be aV simple coilspring 2| mounted onthe stud I8, so that one end bears against the lowerwall of the shutter housing I I and the other end is cradled in a notchor opening in the tab`22 formed integral with the shank of the exposureblade I9.

The aperture blade I'I is provided with an opening 23 adapted toregister with the opening I3 between the lenses Il and I5 when theaperture blade is rotated about the stud I8 to the proper position. Theaperture blade Il also has a studZII iixed thereto on which is rotatablymounted a small pinion 25 and a flywheel 26 of suitable mass that areforced or pressed together so that they will rotate as a single unit.

The exposure blade is provided with an exposure window 2I and hasstamped out an arcuate set of gear teeth 28 adapted to mesh with thepinion 25 as theexposur'e blade rotates about the stud 20. I heoutermostend "of the exposure blade is formed with a/projecting tab' 29, 'therear portion of which is bent outwardly,

ing wall l2 and is preferably restrained in its;

pivotal movement by a friction or spring washer 31 (see Figure 2)between the lieadofthe1 stud 33 and the body of the switch member 35.This* switch member thus tends to stayin oneposition until positivelymoved to a d iierent position.-

The switch member preferably has two arms 38p @ident with; the actualexposure. i blade thencontinues its rotation in a counterand 39, theends of which arel bent toiolmoutr.

wardly projecting tabs 40 and 4|', respectively;

The shutter housing is provided with a p airot large headed rivets 42and 43 mounted in the upper Wall of the shutter housing. andconneotedelectrically inside,V the, housing to the switch mem-.- ber- 3 5.andthe. contact. member 44. For example, the contactmember 44 .maybeixedto thewall I 2 of, the .housing l` in -a positionv tobe.-contacted byv the.. arm 3.9 of the switch member when this memberis. rotated clockwise.` The contactr 44, which mayl be a simple, rivet,is connected eleo-v trically. by wires or. o ther means; -(not shown) totherivet4 or contactI button. 43, and the. switch member 35 through thestud 36 is, connected electrically by wires. or other means (notshown).to therivet or contact button. 42.

In thooperation, ofiacameraemploying this shutter,v the. battery orlother power source and the'flash lamp areconnected inseries. with eachother and with the contact buttons 42and 43, as. shown in Figure, 9`. vThus, whenA thev switch arm 35..is moved o.ver the, Contact, al circuitis closed which, sets.. off. the ilash, lamp.v pOf, course, the.housing. I is. constructed of. metal or other conductingmateriahtheswitch35l contact mem: ber 44 andcontactbuttons-llz and 43`should be. suitably insulated..

They shutter. mechanism, may. be operated, by a. cable. releaseor anyother suitable means.. such as .the rod.46 the. lower. end of which ispiyotally attached over. the stud and the, upper end of which,y may beexposed or` coxreol` by a, cap .41., mounted. for vertical`reciprocation ina suitable. openingzfl in the upper wallof the housingII'.

In theoperation of. this mechanism. as.wil1. be seenby referring toEFiguresl, 3J land 5., the. parts normally. orina. position of. rest..are. ar.- ranged as shown in Figure, L wth the switch member 35 spacedfrom the contacty member -44 andthe two shutter blades; l1. andvI9covering the exposure openingv I3 in the. camera housing and heldinthis position by the. spring 2|.

When the rod 461s moved downward,.as, by manual pressure. on the cap`.47,l the aperture blade Il (seehFigure 3;) isrotated in a counter.clockwise direction, compressing thespringuzl. The exposure blade i9,however, does. Ilot. rotate at this stage but byreason of itsmountingveccentric toy the .stud I8 is shifted. lengthwise. s ol thatthe forward edgeof the tab 29.slides downalong the iixed `projection 3|.This movement continues until the position in liigureA 3 is; reached, atwhich point the.. tab 29v is just about toslidefs free ofy theprojection 3|. A t; this stage, the aperture 23 in the aperture bladeI-'l is approachingbut has notA quite reached a position concentric withthe-exe posurevopening I3 in the camera housing:

As; the. exposure.; blade I9 slides: free. the aperta exposure, and thetab 29 on the exposure blade strikes the tab on arm 38 of the switch 35.rotating this switch member in a clockwise direction so that its arm 39slides over and frictionally engages the contact member 44. Thisposition isshowgn Ainlligure 4, andqcompletes the circuit tothe,flash-,lampslightly in advance. of the passage of the window 21 in theexposure blade over the exposure aperture I3 to expose the lm behind it.

This advance completion of the electrical circuit Aallows the rightamount of time interval for the-.hash lamp to reach its peak light valuecoin- The exposure clockwise direction, completing the exposure andleavingthe switch arm in the closed position as seenin Figure 5.

The rotation of the, exposure blade is caused by thenspringy 2 .I.bearing against the tab; 225and duringthe exposure, the spring losessomobut notx al1,.of its compression. 'lheeeor teeth. 2.8, on theexposure blade during. itsrotat-ion ina counterclockwisedirection aboutthe stud 20; are at all. times inengogement. with the pinion 2-5and-causing .rotation of. the` flywheel 26.@ The massofthis, flywheelmay.be made of thev right value tocontrol, the speed of the.exposure -b1adeso that the V.time interval betweenthe.y closing of the flash switch andthe exposure and. alsoithe time interval. for the window 21 to move overthe exposure opening are always. uniform, accurate land closelycontrolled. It, is. not necessary in this arrangement, as it is with somany camera shutters, to provide a spring of exactly the right force.Ordinarily, the strength of, the. spring determinesthe speed ofoperation of the parts.. but in. thiscase the strength ofthe spring notas. critical asusuah and aspring that is strong ture. blade` arrives..at the. proper.-positieny for the".

enough to perform all of. the, rieoessaryV operations caribe. used.with. a. considerable tolerance in. its strength.l v

. yline.exposure havingv been completed, the-parts return toapositionof. rest under. the influence of.v

the spring 2| as s oonas the, rod 46 andoap. 41 are released; At thisstage the tabs 32 and/33 en the two., b lades and I9. are, inconta-otwith each athen, thus limiting. further .relative movement oithe twoblades so. that. the force, ofthe spring y 2| causes..Simultaneous, rotation of the two blades aboutl the stud, I3, returningthemv tothe position ofrest. shown in Figure 1 Asy the blades return,the upper, inclined edge of the. aperture bladel I 1 strikes, the tab 4|of the, switch member 35. rotate4 ing the switch member in acounterclockwise direction until its.: arm39 is,fre e` and clear.v ofthe contact member 44. Byvroason of the. frio.-A tional mountineof the.switch armY 35 on thostud 36. they-shrine. arm retains its, position4until it is positively` rotated again by the) exposure-.blade of` the.shutter to. einsame Switch-again.. at. the same .time the inclinedportion 3-0, of, tab 29. on bladey |9causes they taby to ride overproject-ion 3.Io1earins the switoharm. t8.v and. restoring the exposure.blade. to-a position for making thee-next exposure.

. -It willy be apparent to those skilled in the -art that this .shuttermechanism iscapableormassproduction with, very consistent results Thetwo blades may be made by simple stampingfoperaa tionsjusing. thinsheet. material, such as steel; the pinion andvflywheel can be. simplevdie` castings;- fltting together with a press fit; and the parts may.bef readily mounted or assembled by simple riveting operations.

Thun the entiroishutterf mechanism is economical to construct as well aspositive and consistent in its operation. Only one spring is needed forthe entire mechanism and the exact strength of this spring is notcritical.

In addition, the flash switch unit is positive in operation and notlikely to become fouled by corrosion because of the positive andcontinuous frictional engagement that the switch arm 39 makes with theContact member 44, This is of substantial advantage compared with switchmembers that rely upon a spring element or upon a momentary wipingcontact for completing the electrical circuit.

The terms and expressions which I have employed are used as terms ofdescription and not of limitation, and I have no intention, in the useof such terms and expressions, of excluding any equivalents of thefeatures shown and described or portions thereof, but recognize thatvarious modiiications are possible within the scope of the inventionclaimed.

I claim:

l. In a camera shutter mechanism, a housing having an exposure openingtherein, a blade pivotally mounted in the housing and having an aperturethat registers with said opening when the blade is rotated from itsnormal position of rest, an exposure blade pivotally mounted on saidIirst blade for making an exposure when rotated in the same directionfollowing' rotation of said rlrst blade from its rest position, a flashswitch member mounted in said housing for pivotal movement, an electricContact disposed in the path of movement of said member so as to make asliding contact therewith upon rotation of the member, said switchmember having a portion engaged by said exposure blade at the start ofits rotation to make an exposure and to rotate the switch member intoengagement with said contact, and said switch member having anotherportion engaged by one of said blades to return the member to itsoriginal position when the blades return to their rest position.

2. In a camera shutter mechanism, a housing having an exposure openingtherein, a blade pivotally mounted in the housing and having an aperturethat registers with said opening when the blade is rotated from itsnormal position of rest, on exposure blade pivotally mounted on said rstblade for making an exposure when rotated in the same directionfollowing rotation of said iirst blade from its rest position, springmeans for rotating said exposure blade to make an exposure, a flywheelfor regulating the speed of said exposure blade when rotated by saidspring means, a flash switch member mounted in said housing for pivotalmovement, an electric contact disposed in the path of movement of saidmember so as to make a sliding contact therewith upon rotation of themember, said switch member having a portion engaged by said exposureblade at the start of its rotation to make an exposure and to rotate theswitch member into engagement with said contact, and said switch memberhaving another portion engaged by one of said blades to return themember to its original position when the blades return to their restposition.

3. A camera shutter mechanism which comprises a housing having a lensopening therein, an aperture blade pivotally mounted in said housing forrotation from a position of rest covering said opening to an exposureposition uncovering said opening, an exposure blade eccentrically andpivotally mounted on said aperture blade so that the exposure bladepivot is moved away from said opening as the aperture blade is rotatedtoward its exposure position, a latch engaging an outer portion of theexposure blade to restrain pivotal movement thereof only until theaperture blade reaches exposure position, spring means for rotating saidexposure blade when released by said latch to expose said opening, anoperating member for rotating said aperture blade to its exposureposition, a flywheel to regulate the speed of rotation of said exposureblade after release by said latch, a fixed electrical contact, and a ashswitch member Vpivotally mounted in the housing for rotation from oneposition to another position in sliding engagement with said contact,said member having a portion engaged by said exposure blade afterrelease by said latch to rotate said member into said engaging position,and said member being returned to its original position by one of saidblades when the blades are returned to their rest position.

4. A camera shutter mechanism as dened in claim 3 in which the iiywheelis pivotally mounted on the aperture blade, and the exposure blade hasteeth formed therein to provide an arcuate rack engaging a pinion on theiiywheel.

WILLIAM L. LAWSON.

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